<template>
	<view v-if="goods_info.goods_name">
		<!-- 搜索组件 -->
		<my-search @click="gotoSearch"></my-search>
		
		
		<view class="scroll-view-container">
			<!-- 左侧的滚动视图区域 -->
			<scroll-view scroll-y="true" class="left-scroll-view" :style="{height:wh + 'px'}">
				<block v-for="(item,i) in cateList" :key="i">
				 <view :class= "['left-scroll-view-item' , i === active ? 'active' : '']" @click="activeChanged(i)">{{item.cat_name}}</view>
				</block>
			</scroll-view>
			
			<!-- 右侧滚动视图区域 -->
			<scroll-view scroll-y="true" class="right-scroll-view" :style="{height:wh + 'px'}" :scroll-top="scrollTop">
				<view class="cate-lv2" v-for="(item2,i2) in cateLevel2" :key="i2">
					<view class="cate-lv2-title">
						{{item2.cat_name}}
					</view>
					
					<!-- 动态渲染三级分类的列表数据 -->
					<view class="cate-lv3-list">
						<!-- 三级分类 item -->
						<view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3"  @click="gotoGoodsList(item3)">
							<!-- 图片 -->
							<img :src="item3.cat_icon.replace(/dev/g,'web')">
							<!-- 文本 -->
							<text>{{item3.cat_name}}</text>
						</view>
					</view>
				</view>
			</scroll-view>
		</view>
	</view>
</template>

<script>
	export default {
		data() {
			return {
				//窗口可用高度 = 屏幕高度 - navigationBar 高度 - tabbar高度
				wh:0,
				//分类数据列表
				cateList:[],
				//当前选中的索引
				active:0,
				//二级分类列表
				cateLevel2:[],
				 // 滚动条距离顶部的距离
				    scrollTop: 0
			};
		},
		onLoad(){
			//获取当前系统信息
			const sysInfo = uni.getSystemInfoSync()
			//为wh 窗口可用高度动态赋值
			this.wh = sysInfo.windowHeight - 50
			
			this.getCateList()
			this.getCateLevel()
		},
		methods:{
			async getCateList(){
				const { data:res } = await uni.$http.get('/api/public/v1/categories ')
				if(res.meta.status != 200) return uni.$showMsg()
				this.cateList = res.message
			},
			activeChanged(i){
				this.active = i
				
				//为二级分类列表重新赋值
				this.cateLevel2 = this.cateList[i].children
				
				  // 让 scrollTop 的值在 0 与 1 之间切换
				  this.scrollTop = this.scrollTop === 0 ? 1 : 0
				
				  // 可以简化为如下的代码：
				  // this.scrollTop = this.scrollTop ? 0 : 1
			},
			async getCateLevel(){
				const { data:res } = await uni.$http.get('/api/public/v1/categories')
				if (res.meta.status !== 200) return uni.$showMsg()
				this.cateList = res.message
				// 为二级分类赋值
				this.cateLevel2 = res.message[0].children
				
				// console.log(this.cateLevel2[0].children)
				// console.log(this.cateLevel2.length)
			},
			gotoGoodsList(item3) {
			  uni.navigateTo({
			    url: '/subpkg/good_list/good_list?cid=' + item3.cat_id
			  })
			},
			gotoSearch(){
				uni.navigateTo({
					url:'/subpkg/search/search'
				})
			},
		}
	}
</script>

<style lang="scss">
.scroll-view-container {
  display: flex;

  .left-scroll-view {
    width: 120px;

    .left-scroll-view-item {
      line-height: 60px;
      background-color: #f7f7f7;
      text-align: center;
      font-size: 12px;

      // 激活项的样式
      &.active {
        background-color: #ffffff;
        position: relative;

        // 渲染激活项左侧的红色指示边线
        &::before {
          content: ' ';
          display: block;
          width: 3px;
          height: 30px;
          background-color: #c00000;
          position: absolute;
          left: 0;
          top: 50%;
          transform: translateY(-50%);
        }
      }
    }
  }
}

.cate-lv2-title {
  font-size: 12px;
  font-weight: bold;
  text-align: center;
  padding: 15px 0;
}

.cate-lv3-list {
  display: flex;
  flex-wrap: wrap;

  .cate-lv3-item {
    width: 33.33%;
    margin-bottom: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;

    image {
      width: 60px;
      height: 60px;
    }

    text {
      font-size: 12px;
    }
  }
}
</style>
